Thermoplastic resins have good properties in terms of impact resistance, processability, moldability, rigidity and appearance, and are widely used in various applications, such as automobiles, electric/electronic products, office equipment, home appliances, toys, and stationery.
Recently, with increasing concern about environmental problems, controversy regarding the hazards of thermoplastic resins is also increasing. Particularly, due to unreacted monomers remaining in a thermoplastic resin, there is a problem in that volatile organic compounds (VOCs) are released from the thermoplastic resin at high temperature. Such volatile organic compounds (VOCs) not only cause bad odors, but also have a negative influence on the human body upon long-term inhalation. Therefore, in recent years, attempts have been made to remove or minimize the volatile organic compounds (VOCs) generated from the thermoplastic resins.
Conventionally, in order to remove the volatile organic compounds (VOCs), a method of minimizing the content of residual monomers or oligomers through enhanced devolatilization during polymerization of raw materials or a method of enhancing water-washing through post treatment has been generally employed. However, these methods have problems such as decrease in output of polymer products and yellowing due to increased residence time during manufacturing processes. In addition, these methods have a problem of increase in process costs due to increase in the number of manufacturing processes and process time.
In addition, there has been proposed a method of adding a deodorant such as zeolite to allow residual monomers to be adsorbed thereon or a method of impregnating a thermoplastic resin with water to allow residual monomers to evaporate along with water through a vent during extrusion. However, the method of using a deodorant has a problem in that it is difficult to completely remove VOCs and residual VOCs are likely to be released during injection at high temperature. In addition, the method of impregnating a resin with water has a problem in that the inside of an extruder is likely to be corroded.
Therefore, there is a need for a thermoplastic resin composition which can reduce VOCs and can exhibit good deodorizing properties.